Cementing apparatus for oil and gas wells



Dec 17, l1935- J, F. ROBINSON ET AL 2,024,662

CEMENTING APPARATUS FOR OIL AND GAS WELLS Dec. 17, 1935. J, F. ROBINSON Er AL CEMENTING APPARATUS FOR OIL AND GAS WELLS 5 Sheets-Sheet 2 Filed April 25, 1933 m www ma. J

nu ,mw #Ha ma MW Dec. 17, 193s. J. F. ROBINSON E, AL 2,024,662

CEMENTING APPARATUS FOR OIL AND GAS WELLS MMM/m36 'atenteci Dec. 17,

UNITED STATES PATENT OFFICE Jay French Robinson, Pittsburgh, Joseph M.

Chilcote, Wellsboro, Tioga, Pa.

and Wallace H. Haupt,

Application April 25, 1933, Serial No. 667,870 13 cmms. '(01. 16e-1) This invention relates to new and useful im provenients in cementing apparatus for oil and gas wells.

In our cio-pending application covering improvements in cementing apparatus for oil and gas wells, Serial No. 642,290, iiled November 11, 1932, issued as patent 1,922,780, we have diS- closed and claimed a novel form oi cementing' plug which is ci exceedingly simple construe-- tion, which enables the user oi the device to accurately determine at all times during the cementing oi an oil or gas well, just how the work is progressing; to accomplish a proper ce inenting of the well with the minimum amount of cementing material; and to accomplish said ccmenting operation with only a very small amount of material, plug equipment and the like to be drilled after the cement has set or hardened.

This prior application structure is extremely eicient in its operation but, due to the use of a position determining disk xed in the casing shoe and which prevents the passage of any implement beyond the location of the disk, when any caving of the well wall takes place, the extent of the caving cannot be determined and it is impossible to remove the caving material.

It is the primary object of the invention to provide cementing apparatus which will possess all of the advantages oi our prior structure and in addition will permit the presence and amount of cavings to be determined and the existing cavings removed.

A further important object of the invention is to provide a cementing plug nose or cage which is constructed to permit it to be attached to the plunger portion of the plug to complete the plug assembly or to a conventional bailer to enable the bailer and nose to be conveniently manipulated, by means of a sand line attached to the bailer, to determine the exact location of the bottom of the casing with respect to the bottom of the well.

Still a further object of the invention is to.' provide an improved plug nose or cage and cooperating casing seat.

Other objects and advantages of the invention will be apparent during the course of the following description:

In the accompanying drawings forming a part of this specification and in which like numerals are employed to designate like parts throughout the same,

Figure 1 is a vertical sectional View of a casing shoe attached to the lower end of a string of casing sections with a cementing plug illustrated in elevation and operatively associated with the casing shoe,

Figure 2 is a vertical sectional view of the cementing plug illustrated in elevation in Figure l.

Figure 8 is a top plan view oi the cage or plug nose illustrated in Figures 1 and 2,

Figure l is a transverse sectional view of the cage or cementing plug nose,

Figure 5 is a plan View of a cage seat or ring which is shown in elevation and section in Figures l and 2, respectively,

Figure 6 is a detailed plan view oi a spacer 15 disk employed as an element oi the plunger assembly for the cementing plug in Figure 1 and 2,l

Figure 'I is a detailed plan view oi a spacer block employed as an element of the plunger assembly,

Figure 8 is a vertical sectional view oi a casing 20 shoe and one section of a string oi casing sec. tions with a slightly modified form of cement= ing plug, cage and cage seat,

Figure 9 is a vertical section view of the cage 25 or plug nose illustrated in Figure 8 with a clevis operatively associated therewith and employed for attaching the cage or nose to a conventional bailer, and

Figure 10 is a detailed view of the structure 30 shown in Figure. 9.

In the drawings, wherein for the purpose of illustration, is shown preferred embodiments of this invention and particularly in Figures 1 to 7, inclusive, the numeral il designates one section of a string of well casing sections which has threadedly connected to its lower end a casing shoe l2. This shoe is formed adjacent its lower end with an annular depression i3 adapted toi receive a seating ring lil which is split at l5 40 to permit the ring to be sprung into the annular depression I3. For the purpose of preventing rotation of the ring in the depression and for preventing unintentional compression of the ring which would permit the same to be displaced 45 from the depression, a pair of set screws IB are threaded. through the wall of thecasing shoe I2,- to have their inner' extremities occupy the space between the ends of the split ring i4. It will be noted that the ring I4 is provided with a tap- 50 ered seat Il which has its maximum diameter at the upper end of the ring. The ring is formed with an annular extension I3 which is provided with a tapered guiding surface I9, the function of which will be described at a later point.

The cementing plug illustrated in Figures 1 to 7, inclusive, includes a cage or nose portion 20 and a plunger portion 2 I. The nose portion consists ofv a head 22 which is provided with a peripheral tapered shoulder 23. This tapered shoulder or surface is adapted to mate with and seat on the tapered seat surface I1 of the ring I4 during certain operations of the device. The head 22 is formed with a socket or depression 24 and a centrally located aperture 25. Depending from the lower edge of the head 22 area plurality of longitudinally extending, circumferentially spaced ribs 26 which gradually taper toward their lower ends in both circumferential and radial directions. The lower ends of these ribs 26 have formed integrally therewith a ring-like terminus 21. It will be noted by inspection of Figures l, 2, and 4 that the ring-like terminus 21 is connected with the inner edges of the extremities of the ribs so that the ribs will be positioned radially outwardly of this terminus.

. The plunger portion 2| is completely disclosed and described in our foremention-ed co-pending application, Serial No. 642,290. It therefore will be only briefiy described in connection with this device. Starting with the end of the plunger 2| which is adjacent the head 22 of the cage 20, the plunger structure includes a spacer disk 2S. This disk may be made of any suitable material, such as leather, and when the entire plug is assembled rests directly upon the fiat top surface of the head 22 of the cage 23. Positioned next to the spacer disk 28 is ai cup-like packer member 29 formed of leather, or the like. Next to the packing member 29 is a wooden or cast iron spacer block 39 which is partly received within the cavity of the cup. Next to the spacer block 30 is a second cup-like packing member 3| and two or more wooden or cast iron spacing blocks 32 are arranged next to the packing 3|. The inner one of these spacing blocks 32 is substantially entirely received within the cavity of the cup-like packing 3|. The upper spacing block 32 has positioned thereagainst a third cuplike packing member 33 which has arranged in its` cavity a metal washer or disk 34. All of the elements 29 to 34, inclusive, are provided with central, axially aligned apertures which receive a securing bolt 35 which passes downwardly through all of these apertures into said elements and also through the aperture 25 formed in the head 22 of the cage. A securing nut 36 is threaded on the lower extremity of the bolt 35 for drawing all of the elements of the plunger assembly tightly together and for connecting the cage and the plunger assembly.

The process of cementing an oil or gas well with the cementing plug structure illustrated and described in connection with Figures l to 7, inclusive, is as follows: Before the string of casing sections is lowered into the well, the casing shoe l2 is properly screwed on the lower end of the string. The seating ring I4 also is properly positioned within the depression I3 of the shoe |2. The casing string is then lowered into the well in the usual manner until the casing shoe is positioned within approximately twenty feet of the bottom of the hole and the string of casing sections then is suspended in this position. The location of the bottom of the string of casing sections may be determined by lowering a bailer into the well through the bore of the casing. Cement is then mixed to the proper consistency and dumped into the hole until the cavity below the pipe is filled and the pipe filled up to twenty or more feet. A bailer again may be lowered into the casing until it contacts with the top of the cement to determine whether sufficient cement has been poured into the hole. The plug assembly then is placed in the casing and forced to the top of the cement by means of the bailer. After which suflicient water is run on top of the plug to force it down until the head of the cage 2) rests upon the seating ring I4. The seating of the cage on the ring may be determined by again lowering the bailer into the casing. The cement which was formerly on the inside of the casing now has been forced outwardly of the cas ing into the well hole and partly around the outside of the casing. After suiiicient water has been run on top of the cementing plug assembly to insure the cage remaining seated on the ring I4, the casing then is lowered slowly until the lower end of the casing shoe l2 is seated on the bottom of the well hole. By thus lowering the casing, a volume of cement equal to the volume of the amount of casing lowered has been forced up and around the outside of the casing which gives an additional assurance that there is plenty of cement between the casing and wall to make a good job. The bailer is again lowered through the casing to make certain that the cage has remained seated on the ring I4 during the lowering of the casing. After the cement has had sufiicient time to harden, the cementing plug is drilled out and the hole drilled in in the usual manner.

It will be noted that the cage is of frame or skeleton-like formation and that the various ribs 25 and ring-like terminus 21 will be imbedded in the cement. The ribs 26 will prevent rotation of the plug assembly during the time that the plug is drilled out due to the fact that these ribs are imbedded and anchored in the hardened cement. The ring-like terminus 21 will form an anchor in the hardened cement which will present axial outward movement of the plug. This terminus, also, will assist the ribs 26 in preventing rotation of the plug assembly during the subsequent drilling operation.

In Figures 8 to 10, inclusive, there is shown a modified form of the cage or plug nose and seating ring. In this arrangement, the lower casing section 31 has threadedly connected thereto a casing shoe 38. The shoe is provided with an internal shoulder 3S arranged at the lower extremity of the internally threaded portion 40 employed for connecting the shoe to the lower casing section 31. Due to the mating taper 4| of the threadedly connected portions of the casing section 31 and shoe 38, the lower end of the section 31 will be spaced from the shoulder 39 of the shoe when the casing section and shoe are completely connected. The space between the lower extremity of the casing section 31 and the shoulder 39 forms a depression Threadedly or otherwise secured in this depression` is a ring 43. This ring is provided with a tapered internal seat 44 and an oppositely tapered guiding surface 45. This seating ring 43 is not split and therefore must be assembled in the shoe 38 prior to the connection of this shoe with the casing section 31.

The cementing plug assembly is the same in this modification of the invention as the assembly described in detail in connection with Figures l to 7, inclusive. The saine reference numerals, therefore, will be applied to the Various cage and plug elements of this plunger assembly and the description of these elements will not be repeated. The head 22 of the cage 20 is modified 75 in this form of the invention. In addition to having the central aperture 25 for receiving the bolt 35, the head is further provided with two apertures 45 which are spaced laterally on opposite sides ofthe aperture E5. These apertures 46 are of elongated formation and are intended to receive the coupling arms 4l of a clevis 48. The lower ends of these arms 41 are formed integrally with a head 49. Due to the hollow construction of the cage 2G, the clevis may be inserted upwardly through the bore of the cage and the arms 47 passed through the elongated apertures 46 until the clevis and cage are assembled in the manner illustrated inl Figures 9 and 10. A connecting bolt 5D may be connected to the extremities of the arms 41. This clevis 48 is employed for connecting the cage 20 to a conventional bailer and, it will be noted, that when the cage is connected to a bailer the plunger assembly is not in use. The cage, in this form of the invention, therefore, is adapted for being used as a part of the plug assembly or in combination with a bailer.

The process of cementing a well with this modied form of structure is as follows: The casing shoe 35il with the seating ring 43 is properly connected to the lower section of a casing string. The casing then is run into the well in the usual manner and lowered to approximately twenty feet ofthe bottom of the well and then suspended at that position. The cage 2li, attached to a conventional bailer by means of clevis 48, is then lowered into the casing by means of the conventional sand line until the head 22 of the cage rests upon the tapered seat surface 44 of the ring 43. By means of measurements on the sand line, the location of the casing shoe 28 with respect to the bottom of the well may be determined. After the location of the casing shoe has been determined, the cage and bailer are withdrawn from the well and the cage removed from the bailer. The bailer may then be lowered into the well to determine if the well wall has caved. Markings on the sand line may be employed for this purpose. If cavings are present at the bottom of the well the bailer may be employed for removing the same. After the cavings have been cleaned out of the well, the proper amount of cement is prepared and dumped into the well until the casing is filled for approximately twenty feet from the lower extremity of the casing shoe. The entire plug assembly, including the cage 20 and the plunger 2|, then is placed into the casing and the cementing operation carried out in the same manner as described in connection with the form of the invention shown in Figures 1 to 7, inclusive.

The seating rings I4 and 43 have each been described as being provided with a tapered guiding surface at their lower ends. These guiding surfaces function to guide the bailer or other tool during its upward movement past the seating rings after the bailer has been lowered into the bottom of the well through the bore of the casing. It will be noted that in both forms of this invention, the seating rings are provided with central openings of sufficient diameter to permit the free passage of a bailer, or other implements, therethrough. A bailer or the like, therefore, may be employeo't for removing cavings prior to performing the cementing operation.

It is to be understood that the forms of this invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of the invention or the scope of the following claims.

Having thus described our invention, we claim:

l. In cementing apparatus for oil and gas wells, the combination with a well casing, of a depression formed in the inner surface of said casing adjacent its lower end, a ring positioned in said depression and having a tapered seat` formed on the interior thereof and a guiding surface tapered in the opposite direction to the seat, and a cage adapted to be positioned in said casing and having a shoulder to mate with and rest upon said seat, said cage having a head formed with a pheripheral surface to engage the seat of said ring, a plurality of ribs depending from the head and a ring shaped terminus carried by the ends of said ribs.

2. In cementing apparatus for oil and gas wells, the combination with a well casing, of a depression formed in the inner surface of said casing adjacent its lower end, a ring positioned in said depression and having a tapered seat formed on the interior thereof and a guiding surface tapered in the opposite direction to the seat, and a cage adapted to be positioned in said casing and having a shoulder to mate with and rest upon said seat, said cage having a head formed with a peripheral surface to engage the seat of said ring, a plurality of ribs depending from the head and a ring shaped terminus carried by the ends of said ribs, said terminus being of less diameter than said head and said ribs being arranged radially outwardly of the periphery of said terminus.

3. In a cementing apparatus for oil and gas wells, the combination with a well casing, of a depression formed in the inner surface of said casing adjacent its lower end, a seating ring positioned in said depression, and a cage adapted to be positioned in the casing and to rest upon said ring, said cage having a head formed with a peripheral surface to engage the seat of said ring, and a skeleton like guiding section depending from said head to be imbedded in and held by the cement when it hardens to prevent turning and withdrawal of the cage relative to the cement.

4. In cementing apparatus for oil and gas wells, the combination with a Well casing, of an annular depression formed in the inner sur face of said casing adjacent its lower end, a seating ring threaded in said depression, and a skeleton like cage adapted to be positioned in the casing and to rest upon said ring.

5. In cementing apparatus for oil and gas wells, the combination with a well casing, of an annular depression formed in the inner surface of said casing adjacent its lower end, a split seating ring sprung into the depression, and a cage adapted to be positioned in said casing and to rest upon said ring.

6. In cementing apparatus for oil and gas wells, the combination with a well casing, of an annular depression formed in the inner surface of said casing adjacent its lower end, a split seating ring sprung into the depression, means for preventing turning and undesired contracting of said ring and a cage adapted to be positioned in the casing and to rest upon said ring.

'7. In cementing apparatus for oil and gas wells, the combination with a casing shoe, of a ring mounted in said shoe and having a tapered seat, a cage adapted to be positioned in said shoe and having a head formed with a tapered peripheral shoulder to rest upon said tapered seat and a frame-like guiding and anchoring portion depending from said head and means for eiecting movement of the cage relative to the casing shoe.

8. In cementing apparatus for oil and gas Wells, the combination with a casing shoe, of a ring mounted in said shoe and having a tapered seat, a cage adapted to be positioned in said shoe and having a head formed with a tapered peripheral shoulder to rest upon said tapered seat and a frame-like guiding and anchoring portion depending from said head, means for effecting movement of the cage relative to the Casing shoe and means for anchoring the forementioned means to the cage.

9. In cementing apparatus for oil and gas Wells, the combination with a casing shoe, of a ring mounted in said shoe and having a tapered seat, a cage adapted to be positioned in said shoe and having a head formed with a tapered peripheral shoulder to rest upon said tapered seat and a frame-like guiding and anchoring portion depending from said head and a clevis for connecting the Same to a bailer to effect movement of the cage relative to the casing shoe.

10. In cementing apparatus for oil and gas wells, the combination with a casing shoe, of a ring mounted in said shoe and having a tapered seat, a cage adapted to be positioned in said shoe and having a head formed With a tapered peripheral shoulder to rest upon said tapered seat, a frame-like guiding and anchoring portion depending frorn said head and a plunger structure for eiiecting movement of the cage relative to the casing shoe.

11. In cementing apparatus for oil and gas wells, the combination with a well casing, of a depression formed in the inner surface of said casing adjacent its lower end, a ring positioned in said depression, and a cage adapted to be positioned in said casing and rest upon said ring, said cage having a head formed With a peripheral surface to engage said ring, a plurality of ribs depending from the head, and a ring shaped terminus carried by the ends of said ribs.

12. In oementing apparatus for oil and gas Wells, the combination with a Well casing, of a depression formed in the inner surface of the casing adjacent its lower end, a ring positioned in said depression, and a cage adapted to be positioned in said casing and rest upon said ring, said cage having a head formed with a peripheral surface to engage said ring, a plurality of ribs depending from the head and a ring shape terminus` carried by the ends of said ribs, said terminus being of less diameter than said head and said ribs being arranged radially outwardly of the periphery of said terminus` 13. In cementing apparatus for oil and gas wells, the combination with a well casing, of a seating ring secured in said casing, and a cage adapted to be positioned in the casing to rest on said ring, said cage havng a head formed with a peripheral surface to engage the seat of said ring, and a skeleton like guiding section depending from said head to be embedded in and held by the cement when it hardens to prevent turning and Withdrawal of the cage relative to :the cement.

JAY FRENCH ROBINSON. JOSEPH M. CHILCOTE. WALLACE H. HAUPT. 

